How to Demonstrate Inconsistent Disciplinary Treatment in Dismissal Cases

In unfair dismissal claims in England and Wales, inconsistent disciplinary treatment is a key indicator of potential procedural unfairness. Employment Tribunals assess whether an employer has treated employees involved in similar misconduct or performance issues in a consistent and reasonable way.

Under the Employment Rights Act 1996, a dismissal must be fair in both reason and procedure. Even where misconduct or capability is established, inconsistency in how disciplinary decisions are applied can undermine fairness and support a successful claim.

Demonstrating inconsistency involves comparing how other employees were treated in similar circumstances and assessing whether differences in outcome can be objectively justified.

Legal Framework for Consistency in Disciplinary Decisions

Employment Rights Act 1996

Section 98 requires employers to show:

• A potentially fair reason for dismissal
• A fair and reasonable process
• A decision within the range of reasonable responses

Consistency is part of procedural fairness under this framework.

ACAS Code of Practice

The ACAS Code of Practice on Disciplinary and Grievance Procedures requires employers to act reasonably and fairly. While it does not explicitly mandate identical outcomes, tribunals expect:

• Reasoned and consistent disciplinary decisions
• Fair treatment across employees in similar situations
• Objective justification for any differences

Failure to act consistently can increase compensation awards by up to 25% in some cases where ACAS Code breaches are found.

What Counts as Inconsistent Disciplinary Treatment

Inconsistent treatment occurs when:

• Employees engaged in similar misconduct receive different sanctions
• One employee is dismissed while another receives a warning for comparable conduct
• Decision-making appears arbitrary or influenced by irrelevant factors
• Similar procedural breaches are handled differently without justification

Tribunals focus on whether differences in treatment are reasonable and explainable.

Step 1: Identify Comparable Cases

To demonstrate inconsistency, it is necessary to identify employees who are:

• Employed by the same organisation
• Subject to the same or similar disciplinary policies
• Involved in similar misconduct or performance issues
• Managed by the same or comparable decision-makers

Examples include:

• Two employees accused of similar conduct breaches
• Staff with comparable performance issues
• Employees involved in similar policy violations

Step 2: Gather Evidence of Differential Treatment

Relevant evidence includes:

• Disciplinary records of other employees
• HR policies and decision logs
• Emails discussing disciplinary outcomes
• Witness statements confirming different treatment
• Anonymous or redacted case summaries (where disclosure permits)

Employment Tribunals require disclosure of relevant documents, including comparator evidence where applicable.

Step 3: Analyse the Differences in Outcomes

Once comparator cases are identified, assess:

• Whether similar allegations led to different sanctions
• Whether disciplinary procedures were applied differently
• Whether mitigating factors were treated consistently
• Whether warnings were issued in one case but not another

Key question: would a reasonable employer have treated both employees similarly?

Step 4: Assess Justifications for Differences

Employers may argue that differences in treatment are justified. Common justifications include:

• Differences in disciplinary history
• Severity or impact of misconduct
• Level of seniority or responsibility
• Strength of evidence in each case
• Mitigating circumstances

Tribunals will assess whether these explanations are genuine, documented, and reasonable.

Step 5: Identify Patterns of Inconsistency

Inconsistency may be demonstrated through patterns such as:

• Repeated harsher treatment of one individual or group
• Leniency shown to senior staff compared to junior employees
• Lack of alignment with disciplinary policy
• Unexplained deviations from standard procedure

Patterns are often more persuasive than isolated examples.

Types of Inconsistent Treatment in Dismissal Cases

1. Different sanctions for similar misconduct

• One employee receives a warning
• Another is dismissed for the same type of breach

2. Selective application of disciplinary procedures

• Formal process used for some employees
• Informal handling for others

3. Unequal consideration of mitigation

• One employee's mitigating circumstances accepted
• Another's ignored without explanation

4. Disparate investigation standards

• Thorough investigation in one case
• Minimal or rushed investigation in another

How Tribunals Assess Inconsistency

Employment Tribunals apply the “range of reasonable responses” test. They consider:

• Whether differences in treatment are explainable
• Whether the employer acted within a reasonable range of disciplinary options
• Whether the decision was arbitrary or discriminatory
• Whether policies were applied consistently

Importantly, tribunals do not require identical outcomes, but they do require rational justification for differences.

Common Evidence Used to Prove Inconsistency

Documentary evidence

• HR disciplinary records
• Redacted comparator case files
• Internal investigation reports
• Emails discussing disciplinary outcomes
• Policy documents showing standard procedures

Witness evidence

• Employees who experienced different treatment
• Managers involved in previous disciplinary decisions
• HR personnel confirming standard practice

Statistical or pattern evidence

• Multiple similar cases showing different outcomes
• Evidence of systematic leniency or harshness

Common Employer Defences

Employers often argue:

Cases are not truly comparable

Differences in facts, severity, or context are highlighted to distinguish cases.

Different decision-makers were involved

Employers may argue variation reflects managerial discretion.

Policy allows discretion

Disciplinary policies often state that outcomes depend on circumstances.

Mitigating factors differ

Prior conduct, warnings, or performance history may justify different outcomes.

Practical Steps to Build a Claim

To demonstrate inconsistent treatment:

• Obtain full disciplinary records through disclosure
• Identify comparator employees and cases
• Build a structured comparison table
• Link evidence to specific disciplinary policies
• Prepare witness statements supporting inconsistency claims
• Align findings with unfair dismissal legal tests

Common Mistakes in Inconsistency Arguments

Comparing non-comparable cases

Differences in severity or context can weaken the argument.

Relying on assumptions rather than evidence

Tribunals require documented evidence, not speculation.

Ignoring employer justification

Failure to address possible explanations reduces credibility.

Focusing only on outcome, not process

Procedural differences are often as important as final sanctions.

Practical Impact on Unfair Dismissal Claims

Demonstrating inconsistent disciplinary treatment can:

• Support a finding of unfair dismissal
• Strengthen arguments on procedural unfairness
• Increase compensation potential
• Influence settlement negotiations
• Undermine employer credibility

It is particularly relevant where dismissal decisions appear arbitrary or disproportionate.

Key Takeaways

Inconsistent disciplinary treatment arises where employees in similar situations are treated differently without reasonable justification. Employment Tribunals assess whether such differences fall outside the range of reasonable responses under the Employment Rights Act 1996. Demonstrating inconsistency requires comparator evidence, careful analysis of disciplinary outcomes, and identification of patterns or procedural disparities. When proven, it can significantly strengthen an unfair dismissal claim.